Second chances aren't guaranteed in life, but the U.S. Supreme Court is being given one to reverse its catastrophic decision allowing unfettered corporate political spending.

All the court needs to do is take up a case involving an organization that's trying to undermine Montana's 100-year-old ban on direct corporate political giving.

A century ago, Montana decided to break the choke hold that the "copper kings" who ran mining companies had over state government. It enacted a tough law prohibiting corporate financing of political campaigns. But now a group that fights environmental rules on land development sees an opening to bring back the past.

American Tradition Partnership says companies should be allowed to spend freely and secretly to influence elections. The state's attorney general disagreed, and in December got Montana's Supreme Court to rule in favor of the state's campaign-finance law. But ATP has appealed to the U.S. Supreme Court, which gives it a chance to correct its earlier ruling.

Because the Washington-based ATP is organized under the federal tax code as a 501(c)(4) group, it can raise and spend unlimited secret funds on elections. Shadow groups like it are an affront to democracy. They can legally dump the funds they receive from secret sources into a super-PAC, which makes the requirement of limited contribution disclosures by the super-PACs a sick joke.

By now, it should be clear that the super-PACs and their enabling shadow groups are drowning out the voices of ordinary Americans by using millions of dollars from an elite billionaires' club to pay for political advertising. Four-fifths of the super-PAC money in this year's presidential race comes from just 90 donors. Voters have few ways to figure out who's behind groups with vaguely patriotic names sprinkled with words like American or freedom to disguise their purposes.

The super-PACs were unleashed by the Supreme Court's 2010 ruling that allows corporate money to finance campaigns. That has resulted in 70 percent of the advertising in the presidential race being negative, compared with only 9 percent in 2008, according to a Wesleyan University study. Of course, negative advertising is known to suppress voter turnout.

Voters know something is wrong. Seventy-eight percent think super-PACs should be illegal, according to a Washington Post-ABC News poll. The Supreme Court should listen to them, the 22 states that have filed briefs supporting Montana's campaign law, and top Republicans — including U.S. Sen. John McCain — who want the nation to take back its elections from corporate bosses.